Red Opalescent Cleoniceras Ammonite from the Cretaceous Seas of Madagascar Cleoniceras Ammonite - Height: 102 mm - Width: 86 mm- 254 g - (1)

Lower Cretaceous (145–100.5 million years) - Excellent Cleoniceras with Red Opal Fluorescence — This lot presents a magnificent specimen of ammonite from the Cleoniceras genus, coming from the famous Cretaceous Madagascar deposits. The fossil, a witness to a marine ecosystem over 100 million years old, has been masterfully sectioned and polished to reveal its intricate internal architecture. The most fascinating feature of this piece is its vibrant iridescence, with dominant flashes of deep red that earned it the commercial name of “Fire Ammonite.” It is an object that blends the scientific rigor of paleontology with the incredible aesthetics of a gem created by nature. Direct observation of the specimen reveals an almost perfectly logarithmic spiral, an icon of natural geometry. The mirror-polished surface acts as a window into time, allowing a view into the chambers (or phragmocone) that the ancient cephalopod used to regulate its buoyancy. These chambers appear filled with deposits of crystalline calcite and other sedimentary minerals, creating a mosaic of colors ranging from earth brown to pearl gray. What makes the specimen exceptional are the complex and delicate suture lines, the junctions between the chamber walls and the outer shell. In this Cleoniceras, they form a filamentous and jagged pattern, a sign of remarkable biological evolution. The color phenomenon that defines this piece is spectacular. When light strikes the surface, intense bursts of ruby red and orange ignite with surprising vividness. This is not pigmentation but an optical structural effect known as iridescence, caused by the preservation of the original aragonite layer that constituted the nacre of the shell. During fossilization, this layer was preserved in ultra-thin laminas. Light, passing through and reflecting off these layers, undergoes diffraction and interference that splits white light into its constituent colors. It is the same physical principle that generates the changing colors of precious opal, turning this fossil into a true organic gem. Ammonites of the genus Cleoniceras lived during the Albian, an early Cretaceous stage, about 113–100.5 million years ago. Madagascar deposits are renowned worldwide for the exceptional preservation state of fossils, often with the original shell partly or wholly preserved, as in this case. The fossilization process in an anoxic, mineral-rich environment allowed the delicate shell structure not to be destroyed but slowly permineralized, thus preserving the incredible optical effect of nacre. For a collector, an ammonite like this represents a piece of great value. The combination of species (Cleoniceras), origin (Madagascar), age (Cretaceous) and, above all, the quality of the “fire” iridescence places it among the most desirable specimens. In addition to its scientific interest, it is an object of extraordinary decorative beauty. Its sculptural shape and its changing colors make it perfect as a visual centerpiece in a modern Wunderkammer, on a desk in a study, or on a library shelf. Owning a Fire Ammonite means keeping a time capsule, a tangible link to the deep history of our planet. Technical details Name: Fossil Ammonite (Genus: Cleoniceras) Classification: Cephalopoda Provenance: Madagascar Geologic period: Cretaceous (ca. 145–100.5 million years) Dimensions: 102 x 86 x 25 mm Weight: 254 g Conditions: Natural specimen, sectioned and polished to expose the inner chambers and iridescence.